Prepare the meat: Cut the pork shoulder and pork belly into roughly 2.5cm (1 inch) cubes. For the pork shoulder, trim off any large pieces of fat but leave some for moisture and flavor. For the pork belly, remove the skin.

Grind the meat: Working in batches to avoid over-heating the grinder, grind the pork shoulder and pork belly through a coarse die (around 8mm or 5/16 inch). If you don't have a grinder, you can finely chop the meat with a very sharp knife, but this is more labor-intensive and may result in a slightly different texture.

Prepare the seasonings: Finely mince the garlic. If using fresh marjoram, chop it finely. Measure out the salt, pepper, caraway seeds, and nutmeg.

Mix the sausage filling: In a large bowl, combine the ground pork shoulder and pork belly. Add the minced garlic, chopped marjoram, caraway seeds, nutmeg, and kosher salt and black pepper. Gradually add the ice water while mixing.

Check seasoning: Fry a small patty of the sausage mixture in a lightly oiled pan over medium heat for about 3-4 minutes, until cooked through. Taste and adjust seasonings if necessary. Remember that flavors will meld and intensify during smoking.

Prepare the casings: Ensure your pork casings have been thoroughly rinsed of salt and soaked in cold water for at least 2 hours (or overnight in the refrigerator). Drain them and have them ready.

Stuff the sausages: Attach the soaked pork casings to the stuffing tube of your sausage stuffer. Feed the casing onto the tube, leaving about 15cm (6 inches) of casing hanging off the end. Begin stuffing the mixture into the casings, filling them firmly but not so tightly that they will burst during cooking or smoking. Aim for a uniform thickness.

Form the sausages: Twist the stuffed casings into individual sausages, each about 15-20cm (6-8 inches) long. Ensure the twists are tight to prevent the sausages from unraveling.

Rest the sausages: Place the formed sausages on a clean baking sheet or rack. Allow them to rest uncovered in the refrigerator for at least 2 hours, or preferably overnight. This allows the salt to cure the meat and the flavors to meld, and also helps the casings dry slightly, which aids in smoke adhesion.

Prepare for smoking: Preheat your smoker to 70°C (160°F). Use a mild wood like applewood or beechwood. If you are not smoking, you can skip this step and proceed to cooking.

Smoke the sausages: Place the rested sausages in the smoker, ensuring they do not touch each other. Smoke for approximately 2-3 hours, or until the internal temperature of the sausages reaches 65°C (150°F). The sausages should develop a light golden-brown color.

Finish cooking (if smoked): After smoking, the sausages are technically cooked but can benefit from further cooking to ensure they are fully done and to achieve a desirable texture. You can boil them gently in water at 80°C (175°F) for 20-30 minutes, or until the internal temperature reaches 71°C (160°F). Alternatively, you can grill or pan-fry them until heated through and nicely browned.

Finish cooking (if not smoked): If you are not smoking the sausages, you can cook them by gently simmering them in water at 80°C (175°F) for about 45-60 minutes, or until the internal temperature reaches 71°C (160°F). You can also grill or pan-fry them.

Cool and store: Once cooked, immediately plunge the sausages into an ice bath for about 10-15 minutes to stop the cooking process and help set the casings. Drain them well and pat them dry. They can be refrigerated for up to 5 days or frozen for longer storage.